Input devices including proximity sensor devices (e.g., touchpads, touch sensor devices, etc.) are widely used in a variety of electronic systems. A proximity sensor device typically includes a sensing region, often demarked by a surface, in which the proximity sensor device determines the presence, location and/or motion of one or more input objects. Proximity sensor devices may be used to provide interfaces for the electronic system. For example, proximity sensor devices are often used as input devices for larger computing systems (such as opaque touchpads integrated in, or peripheral to, notebook or desktop computers). Proximity sensor devices are also often used in smaller computing systems (such as touch screens integrated in cellular phones). Proximity sensor devices may also be used to detect finger, styli, or pens.
Proximity sensor devices may utilize a camera to capture images of an input object within the camera's sensing region. However, if the input object is located in the camera's blind spot, the input object might not appear in the image and thus proximity sensor device might erroneously determine that no input object is present.